package com.wm.walmart.util;

import java.security.MessageDigest;

/**
 * 使用MD5算法加密,支持加盐
 * 
 * @Description:
 * @author QinKui
 * @Date 2019-5-29
 */
public class PasswordEncoder {

	private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5",
			"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

	private Object salt;// 盐值
	private String algorithm;// 加密算法

	/**
	 * 构造一个加密器
	 * 
	 * @param salt
	 *            盐值
	 * @param algorithm
	 *            加密算法
	 */
	public PasswordEncoder(Object salt, String algorithm) {
		this.salt = salt;
		this.algorithm = algorithm;
	}

	/**
	 * 哈希加密
	 * 
	 * @param rawPass
	 *            普通文本密码
	 * @param hashCount
	 *            哈希次数
	 * @return 加密后的密码字符
	 */
	public String encode(String rawPass, int hashCount) {
		while (hashCount-- > 0) {
			rawPass = generalEncode(rawPass);
		}
		return rawPass;
	}

	/**
	 * 普通加密
	 * 
	 * @param rawPass
	 *            普通文本密码
	 * @return 加密后的密码字符
	 */
	public String generalEncode(String rawPass) {
		String result = null;
		try {
			MessageDigest md = MessageDigest.getInstance(algorithm);
			// 加密后的字符串
			result = byteArrayToHexString(md.digest(mergePasswordAndSalt(
					rawPass).getBytes("utf-8")));
		} catch (Exception ex) {
		}
		return result;
	}

	/**
	 * 密码和盐值合并
	 * 
	 * @param password
	 *            普通文本密码
	 * @return 合并后字符串
	 */
	private String mergePasswordAndSalt(String password) {
		if (password == null) {
			password = "";
		}
		if ((salt == null) || "".equals(salt)) {
			return password;
		} else {
			return password + "{" + salt.toString() + "}";
		}
	}

	/**
	 * 转换字节数组为16进制字符串
	 * 
	 * @param b
	 *            字节数组
	 * @return 16进制字符串
	 */
	private static String byteArrayToHexString(byte[] b) {
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++) {
			resultSb.append(byteToHexString(b[i]));
		}
		return resultSb.toString();
	}

	/**
	 * 转换字节为字符串
	 * 
	 * @param b
	 * @return
	 */
	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0)
			n = 256 + n;
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	public static void main(String[] args) {
		String salt = "秦总";
		PasswordEncoder encoderMd5 = new PasswordEncoder(salt, "MD5");
		String encode = encoderMd5.encode("ysd123", 5);
		System.out
				.println("带盐值的MD5哈希五次加密 长度" + encode.length() + "=>" + encode);
		String pwd = "cb0909acffaa236efe62531c523c2b2b";
		System.out.println(encode.equals(pwd));

	}

}